Mailing machines including postage metering systems are known in the art including the DM SERIES of mailing machines available from Pitney Bowes Inc. of Stamford, Conn. A postage metering system applies evidence of postage, commonly referred to as postal indicia, to an envelope or other mail piece (directly or on a label to be applied thereto) and accounts for the value of the postage dispensed.
The modern postage metering systems typically employ one or more microprocessors for general mailing machine control and a secure postal security device (PSD) coprocessor for accounting for postage funds transactions. When controlling an inkjet printer, the main microprocessor may write out columns of indicium data to the inkjet printer subsystem. The main microprocessor may also interface with the PSD to initiate postage accounting and cryptographic co-processing functions as required.
In personal computer math coprocessor systems such as the INTEL387SX processor, the CPU would synchronize transfer of commands and data to the coprocessor using busy status lines. When the coprocessor has the necessary data, it then executes in parallel to the main CPU. The main CPU may then loop to waste instructions while waiting for the coprocessor to be ready to accept additional instructions and/or data required. A WAIT command may be used to synchronize operand transfer.
Accordingly, there is a need for a coprocessor synchronization system that does not waste main processor resources.